Fork for pulpwood and similar materials



Jan. 12, 1965 c. w. GARDNER FORK FOR PULPWOOD AND SIMILAR MATERIALS Filed Aug. 26, 1963 2 Sheets-Sheet 1 INVENTOR.

' CH AQLES W. GARDNER BY w ATTORNEYS Jan. 12, 1965 c. w. GARDNER FORK FOR PULPWOOD AND SIMILAR MATERIALS 2 Sheets-Sheet 2 Filed Aug. 26, 1963 INVENTOR.

CHARLES W. GARDNER AT TORNEY S United States Patent 3,165,345 FQRK FUR PULPWOUD AND SHMILAR MATERIALS Charles W. Gardner, Peoria, Iii, assignor to (Iaterpillar Tractor Co., Peoria, Ill., a corporation of California Filed Aug. as, 1963, Sci. No. 394,547 3 Claims. (Cl. 294-67) The present invention relates to forks of the kind used on tractor-mounted loaders for the purpose of gathering, holding and transporting such material as pulpwood in small log sizes which are handled in large quantities.

It is the object of the present invention to provide a fork with a clamping element for gathering material into the fork and holding it during transportation in which a superior gathering and tighter clamping is obtained as compared to known forks used for this purpose. It is also an object of the invention to provide a fork in which the clamp opens to create a very large space for reception of material and may be closed to a position for clamping even a single small log. It is also an object of the invention to provide a fork having a clamp which closes about a pivot with means to move the pivot toward the fork during clamping movement to obtain an additional inward sweeping or gathering movement which increases the capacity of the fork and facilitates clamping. Further objects and advantages of the invention and the manner in which it is carried into practice are made apparent in the following specification by reference to the accompanying drawings.

In the drawings:

FIGS. 1, 2 and 3 are views in side elevation of a fork and clamp with clamp actuating mechanism embodying the present invention illustrating the clamping means in different positions; and

FIG. 4 is an isometric projection of the same fork.

Referring to the drawings, FIGS. 1, 2 and 3 show only one side of a mechanism, the two sides of which are identical as may be observed from FIG. 4, and the ensuing description will therefore be directed principally to one side of the fork. Furthermore, levers which are uppermost end of one of the upstanding tine portions shown as two matched parts in FIG. 4 will be considered for simplicity as single partlevers in the description of FIGS. 1 through 3, inclusive.

A two tined fork unit is illustrated as having upstanding parts 10 terminating in substantially horizontal tines 11. A clamp which is pivotally supported with respect to the fork unit comprises a pair of arms 12 which terlever 18 which has triangularly spaced pivot points 20,

22 and 24. The pivot point 20 forms a connection between the lever and one of the tine parts 10, the pivot point 22 is connected with the innermost end of a fork arm 12 and the pivot point 24 is connected with extensible means shown as a hydraulic jack 25. The opposite end of the jack is pivoted as shown at 26 with the 10. Consequently, extension of the jack 25, which is accomplished by a conventional hydraulic circuit controlled by the operator of a tractor upon which the fork is mounted, swings the lever in a counterclockwise direction as view in FIGS. 1, 2 and 3 about its pivot 20. This moves the pivot 22 with the clamp member inwardly in the path of an arc struck about the pivot 15 and imparts downward swinging of the clamp assembly toward and through the position shown in FIG. 2 and finally to the position of FIG. 3, where, as illustrated, a single log 28 may be firmly held between the tines and the clamp.

Meanwhile and during this downward swinging motion of the clamp assembly, an inward or rearward motion is also imparted thereto by reason of the movement of the pivot 22 around the pivot 15, as well asinward movement of the pivot 22 resulting from leftward or counterclockwise movement of the lever 18. Thus, for

example the position of the pivot 15 shown in FIG. 2 which is indicated at 15a in FIG. 3 shows clearly that the clamping assembly has moved in its entirety toward the fork, imparting a gathering and clamping effect which is different and superior to that obtained with a simple pivotal movement. Furthermore, the clamp assembly is opened to a very wide angle because of the relative positions of pivots 15 and 22 shown in FIG. 1, thus enabling it to embrace a large number of logs or a large mass o material in its closing movement.

The clamp of the present invention is intended to be mounted on the forward end of a tractor through conventional lift and tilt mechanism such as that ordinarily used in tractor-mounted loader buckets and comprising as illustrated in FIG. 2 lift arms 30 and tilt linkage 31, only the forward ends of which are shown. The lift arms are pivoted as at 33 to a bracket structure 34 fixed to the rear of the fork unit and the tilt linkage is similarly pivoted as at 35 to the same structure so that they may be manipulated to effect tilting of the fork with respect to the ground while it may be raised and lowered by means of the lift arms 30. As shown in FIG. 4 the two tine units are preferably connected by beams 37 and 38 which space and strengthen them. In operation the fork is brought .to the ground in an open position such as illustrated in FIG. 1 and the clamps are then closed by extension of jack 25 to embrace a plurality of logs as indicated in FIG. 2, or to the further position of FIG. 3 where one or two small logs may be embraced and clamped.

A further advantage of the present invention results from the fact that the moment arm which is eifective between the jack 25 and the lever 18 increases materially upon extension of the jack so that the force applied in the clamping action illustrated in FIGS. 2 and 3 is greater than that in the open position of FIG. 1. The relationship of pivots 15 and 22 is also such as to increase the effective moment arm as the clamp assembly approaches its clamping position.

I claim:

1. A material handling fork of the kind described comprising forwardly disposed tines with upstanding parts at their rearward ends, clamp arms, a link pivoted to the clamp arms and to said upstanding parts, a lever pivoted to said parts below said link, a pivotal connection between said lever and said clamp arms, and extensible power means between said parts and said lever to swing the lever rearwardly for rotating the clamp arms toward" a closed position with respect to the tines about their pivotal connection withsaid link and to swing said link down-wardy and rearwardly.

2. The combination of claim 1 in which there are two tines and two clamp arms aligned with the tines and said clamp arms are short enough to permit swinging movement intoclose proximity with the tines and a tongue connecting the forward ends of the clamp arms and'shaped to extend between the tines.

parts and extends rearwardly thereof for pivotal connection with said extensible power means. 7 7

References Cited in thefile of this patent UNITED STATES PATENTS codiint May 12, 1959 Wagner Nov. 1, 1960 

1. A MATERIAL HANDLING FORK OF THE KIND DESCRIBED COMPRISING FORWARDLY DISPOSED TINES WITH UPSTANDING PARTS AT THEIR REARWARD ENDS, CLAMP ARMS, A LINK PIVOTED TO THE CLAMP ARMS AND TO SAID UPSTANDING PARTS, A LEVER PIVOTED TO SAID PARTS BELOW SAID LINK, A PIVOTAL CONNECTION BETWEEN SAID LEVER AND SAID CLAMP ARMS, AND EXTENSIBLE POWER MEANS BETWEEN SAID PARTS AND SAID LEVER TO SWING THE LEVER REARWARDLY FOR ROTATING THE CLAMP ARMS TOWARD A CLOSED POSITION WITH RESPECT TO THE TINES ABOUT THEIR PIVOTAL CONNECTION WITH SAID LINK AND TO SWING SAID LINK DOWNWARDLY AND REARWARDLY. 